NEW YORK -- Moments after Yasuyuki Shibata sat down with his friends to a buffet dinner in the 110-story World Trade Center's Vista Restaurant, his plate hopped off the table, the lights went out and he lost his appetite.

"I was thinking that a plane had hit the building or that an earthquake had hit, like in Tokyo," said Mr. Shibata, 47, a general manager of the cargo freight airline, Nippon Express USA Inc.

When the initial shock wore off, and patrons had milled about for 20 minutes, Mr. Shibata asked a waiter what to do. The restaurant manager suggested everyone walk the 10 floors to the ground.

Then, from the stairwell, came the nastiest shock: Smoke began billowing up, making it impossible to breathe or escape. The windows couldn't be opened. And nobody knew what to do.

"No one panicked, but no one knew what we should do. The stairwell was dark. The emergency lighting was out," Mr. Shibata said.

Moments later, firemen --ed up the stairwell through the smoke with oxygen tanks on their back. Some people in the restaurant began to smash out the windows. Firemen organized the 100 guests into a chain, slowly making their way through the soot and smoke to the street below.

Emerging heaving and soot-covered on the sidewalk in front of the building, Mr. Shibata joined hundreds of others watching paramedics attend to evacuees and many firefighters overcome by smoke.

He clapped a friend on the back, saying, "But we made it. We're so happy."

In variations on the same theme of helpless confusion, Mr. Shibata's story was repeated by dozens of evacuees milling around the yellow police-taped areas around the World Trade Center, the seven-building office complex that includes the second-tallest office buildings in the world, the 110-story twin towers.

Shivering in the cold, their relief at having survived was mixed with outrage about what appeared to be botched safety measures.

People told of escapes complicated by emergency doors chained shut, stairwells with little or no emergency

ventilation, emergency lighting failure, and -- above all -- no one to tell them what to do.

Officials of the Port Authority of New York and New Jersey, which built the stolid structure 20 years ago, refused comment on safety precautions until an investigation was completed.

But other officials said such modern buildings are inherently dangerous because their windows cannot be opened and they pack so many people into one place.

About 100,000 people each day pass through the building, which has 10 million square feet of office space.

"These new buildings are just not as solid as older ones, no matter what regulations they meet," said Steve Wilkes, an inspector with the Department of Labor's Occupational Safety and Health Administration.

His crew ran across the street after the blast to start a preliminary damage report, but was ordered out by firefighters after the fires sent smoke through the complex.

The towers will probably have to be closed for several days, Mr. Wilkes said, until inspectors can determine the extent of the structural damage.

The entire southern tip of Manhattan was paralyzed by the blast. Police cars raced through the narrow streets of the city's oldest section while fire trucks, utility trucks and ambulances jammed the main roads.

Later, when the Empire State Building in midtown Manhattan was evacuated, more of the city became impassable to all but pedestrians. Subway lines were closed, television signals -- which are beamed from the two landmarks -- were disrupted and traffic became impossible.

Marcella Rakitta, a stockbroker for Abaco International Inc., said the afternoon's events caused her company stands to lose considerably because of the trades it could not complete.

Such thoughts, however, were far from even her boss' mind when the explosion caused the "floor to bounce," she said. He told everyone to grab their coats and start walking down.

Like Mr. Shibata, however, the walk became more like a disaster movie than a workout when emergency measures seemed to break down.

"We barely made it through all the smoke," said a soot-covered Ms. Rakitta, who had to walk down 84 flights. "The stairs below our feet got hot, and I wonder what would have happened if there had been a real fire."